Disposable absorbent articles with zones comprising elastomeric components

ABSTRACT

Absorbent articles having a liquid permeable topsheet, a liquid impermeable backsheet, and an absorbent core disposed between said topsheet and said backsheet are disclosed. The absorbent articles include a thermoplastic elastomer joined to or disposed in a stretch zone on at least one component or region of the absorbent article to impart an elastic resistance that provides sizing or shaping capabilities to the article. The absorbent article can be in the form of diapers, pull-on diapers, training pants, sanitary napkins, wipes, bibs, incontinence briefs or inserts.

CROSS RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/557,288, filed Mar. 29, 2004.

FIELD OF THE INVENTION

The present invention generally relates to disposable absorbent articlessuch as diapers, pull-on diapers, training pants, sanitary napkins,wipes, bibs, incontinence briefs or inserts and the like. Morespecifically, the invention is directed to such absorbent articles thathave one or more regions comprising an elastomeric component. Suchcomponents are used in the absorbent articles of the invention toprovide the desired article shape and/or to impart the desired stressand strain properties for improved fit and comfort of the article on thewearer and/or for increased convenience of the user.

BACKGROUND OF THE INVENTION

Disposable absorbent products, such as diapers, training pants,incontinence articles typically include stretchable materials, such aselastic strands, in the waist region and the cuff regions to provide asnug fit and a good seal of the article. Pant-type absorbent articlesfurther include stretchable materials in the side portions for easyapplication and removal of the article and for sustained fit of thearticle. Stretchable materials have also been used in the ear portionsof disposable diapers for adjustable fit of the article. However, itwould be desirable to have materials with improved properties thatbetter define directionality and intensity of the tensile forcesprovided by the contractive portions of the absorbent article. In thisway, such desirable absorbent articles would have the ability to shapeor size to the wearer for better fit and comfort, yet have the abilityto maintain the required tension when on a wearer to achieve sustainedfit and prevent sagging and/or drooping of the article. Absorbentarticles of this kind would result in better fit in various areas of theabsorbent article, e.g., the crotch or waist region of a diaper withresulting improvements in comfort. In the case of a diaper, better fitand comfort can also impart better functional performance such asreduced leakage since the diaper would better conform to the shape of awearer. Such features have heretofore not been available for absorbentarticles.

There are various approaches to providing desirable stretchableproperties in targeted areas of absorbent articles. Stretchablematerials may be strands, films or nonwoven fibrous webs made ofelastomeric materials. Typically, such materials are stretchable in atleast one, and possibly multiple, directions. However, because the filmsor webs are made entirely of elastomeric materials, they are relativelyexpensive, and they tend to have more drag on skin surface, resulting indiscomfort to the wearer of the article. Sometimes, the stretchablestrands or films are laminated to one or more layers of nonwoven webs.Since typical nonwoven webs typically are made of thermoplastic fibers,they have very limited stretchability and, the resulting laminatesprovide considerable resistance to stretch. It is necessary to reducethis resistance substantially in order to make functional stretchlaminates. However, such materials do not have sufficient ability toshape, size or conform to the particularities of the wearer's anatomyupon application.

Other approaches to make stretchable materials are also known, such asstretch-bonded laminates and neck-bonded laminates. Stretch bondedlaminates are made by stretching an elastic strand in the machinedirection (MD), laminating it to a nonwoven substrate while it is in thestretched state, and releasing the applied tension so that the nonwovengathers and takes on a puckered shape. Neck-bonded laminates are made byfirst stretching the nonwoven substrate in the machine direction suchthat it necks (i.e., reduces its CD dimension) then bonding CD orientedelastic strands to the substrate while the substrate is still in thestretched, necked state. This laminate will be stretchable in the CD, atleast up to the original width of the nonwoven before it was necked.Combinations of stretch bonding and neck bonding have also been known todeliver stretch in both MD and CD directions. In these approaches, atleast one of the components is in a tensioned (i.e., stretched) statewhen the components of the laminates are joined together. Again, thesematerials cannot be effectively used in absorbent articles to impart thedesired sizing or shaping features desired by users and wearers ofabsorbent articles.

Zero strain stretch laminates are also known. The zero strain stretchlaminates are made by bonding an elastomer to a nonwoven while both arein an unstrained state. The laminates are then incrementally stretchedto impart the stretch properties. The incrementally stretched laminatesare stretchable only to the extent afforded by the non-recovered (i.e.,residual) extensibility of the laminate. For example, U.S. Pat. No.5,156,793 discloses a method for incrementally stretching anelastomer-nonwoven laminate, in a non-uniform manner, to impartelasticity to the resulting laminate. These stretch laminates behavesimilar to the materials described previously in that they do not havesufficient ability to size or shape to the wearer.

However, in all the approaches above, the materials or laminates aremade separately and then incorporated into the absorbent article. Forexample, the stretch laminates described herein may be cut into theappropriate size and shape, then attached to the desired location in theproduct in a process sometimes referred as the “cut-and-slip” process.Because of the different stretch properties required for differentelements of the product, it is necessary to make a variety of laminateshaving different stretchability and cut the laminates to different sizesand shapes. Several cut-and-slip units may be needed to handle thedifferent stretchability of the stretch laminates and to attach them todifferent locations of the product. As the number of cut-and-slip unitsand/or steps multiplies, the process quickly becomes cumbersome,complicated and expensive. These processes are suitable for modem dayabsorbent article manufacture and are desirable. However, it would alsobe desirable to have absorbent articles having the desired sizing and/orshaping properties, but which can be disposed in or on the absorbentarticle without the need for such complicated and expensive“cut-and-slip” processes.

One alternative to cut and slip processes used by the art is to print anelastomeric composition onto a substrate. Exemplary disclosures includeU.S. Pat. No. 6,531,027 which discusses adhering components of anabsorbent article using an adhesive printing process, PCT ApplicationNo. 03/039420 which discusses printing first and second elastomericcompositions onto a substrate where the compositions differ in at leastone of the following properties: elasticity, melt viscosity,composition, shape, pattern, add-on level, and PCT Application No. WO03/053308, which discusses printing an elastic adhesive onto anextendable substrate to provide a tensioning force during garment wear.

Based on the foregoing, it would be desirable to have absorbent articleswith stretchable material having elastic properties such that it can beextended as desired but still retains the desired degree of elasticityto facilitate sustained fit on the wearer. It would also be desirable tohave such a material that can be disposed easily on any specific area ofthe absorbent article, or component thereof in any desired amount.Additionally, it would be desirable to have such a material or compositehaving elastic properties that can be easily placed in discrete, spacedapart areas of the absorbent article or a component thereof via knowndeposition techniques such as printing (including gravure, offset,letterpress and screen techniques), extrusion coating, roll coating andthe like.

SUMMARY OF THE INVENTION

The aforementioned needs in the art are met by the present inventionwhich provides an absorbent article with a material that has elasticproperties disposed in a predetermined pattern defining a stretch zonethat provides desired elastic directionality and intensity to specificregions of the absorbent article. Such directionality and intensity iscontrolled by controlling the amount, placement and orientation of athermoplastic elastomer that is disposed only on certain zones orregions of the absorbent article or a component thereof.

In accordance with one aspect of the invention, an absorbent article isprovided that comprises a liquid permeable topsheet, a liquidimpermeable backsheet, and an absorbent core disposed between thetopsheet and the backsheet. The article may also include additionalfeatures such as one or more ears or side panels, leg cuffs, andfastener components, elastic belts. In other aspects of the invention,the material used in the absorbent article is provided with one or morestretch zones where the stretch zones may comprise at least a portion ofone or more of the features. In another embodiment of the invention aplurality of the stretch zones are assembled into an array thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a diaper in accordance with the invention;

FIG. 2 is a perspective view showing a diaper chassis having a pluralityof regions with one or more stretch zones or arrays according to theinvention disposed thereon;

FIG. 3 is a perspective view of a pull-on diaper in accordance with theinvention;

FIG. 4 is a plan view of the pull-on diaper of FIG. 2;

FIGS. 5A and 5B are cross-sectional views of the pull-on diaper shown inFIGS. 3 and 4;

FIGS. 6A-I show a diaper embodiment of the present invention in whichthe diaper ears have stretch zones in various designs;

FIGS. 7A and 7B show yet another embodiment of a diaper in accordancewith invention wherein stretch zones are provided to the ears and alongthe absorbent assembly for imparting the desired elastic properties tothe diaper;

FIGS. 8A-D illustrate a diaper in which stretch zones are disposed in avariety of locations to provide several alternative designs for improvedwearer comfort and fit;

FIG. 9 is a plan view of a diaper in accordance with the invention inwhich stretch zones are provided in the diaper ears and the front waistportion;

FIG. 10 is a plan view of a diaper in accordance with the invention inwhich the stretch zones are provided in the rear waist portion such thatthere is at least partial longitudinal alignment with the diaper ears;

FIG. 11 is a plan view of a diaper having stretch zones in the frontcrotch portion in accordance with the invention;

FIG. 12 is another plan view of a diaper in which stretch zones aredisposed along the lateral portions of the diaper in order to providethe desired elastic properties in the leg openings; and

FIG. 13 is a perspective view of a diaper where a stretch zone is usedto provide elasticity to a topsheet.

FIG. 14 is an exemplary stress-strain curve showing “Available Strain”.

DETAILED DESCRIPTION OF THE INVENTION Definitions

The term “disposable” is used herein to describe absorbent articles thatgenerally are not intended to be laundered or otherwise restored orreused as an absorbent article (i.e., they are intended to be discardedafter a single use and, preferably, to be recycled, composted orotherwise disposed of in an environmentally compatible manner).

As used herein, the term “disposed” is used to mean that an element(s)is formed (joined and positioned) in a particular place or position as aunitary structure with other elements or as a separate element joined toanother element.

As used herein, the term “joined” encompasses configurations whereby anelement is directly secured to another element by affixing the elementdirectly to the other element, and configurations whereby an element isindirectly secured to another element by affixing the element tointermediate member(s) which in turn are affixed to the other element.

A “unitary” absorbent article refers to absorbent articles which areformed of separate parts united together to form a coordinated entity sothat they do not require separate manipulative parts like a separateholder and liner.

As used herein, the term “diaper” refers to an absorbent articlegenerally worn by infants and incontinent persons about the lower torso.

By “stretch”, it is meant that the material has the ability to extendbeyond its original length in at least one dimension when subjected to atensile force (i.e., tension) applied in the direction of thatdimension. “Stretch” may be unidirectional, bi-directional, ormulti-directional. The specific “stretch” properties of a material mayvary along any of the stretch vectors. As used herein, stretch includesboth plastic and elastic deformation.

The term “elastic” or “elastomeric” as used herein refers to anymaterial that upon application of a biasing force, can stretch to anelongated length of at least about 125 percent of its relaxed, originallength, without rupture or breakage, and upon release of the appliedforce, recovers at least about 40% of its elongation, preferablyrecovers at least 60% of its original length, most preferably recoversabout 80% of its original length.

The term “inelastic” refers herein to any material that does not fallwithin the definition of “elastic” above.

As used herein, the term elastic resistance describes an elastic forcethat tends to resist an applied tensile force causing a materialprovided therewith to tend to contract to an untensioned configurationin response to a stretching force. Elastic resistance is convenientlymeasured using the method described in the TEST METHODS section below.

“Longitudinal” is a direction running parallel to the maximum lineardimension of the article and includes directions within ±45° of thelongitudinal direction. The “lateral” or “transverse” direction isorthogonal to the longitudinal direction. The “Z-direction” isorthogonal to both the longitudinal and transverse directions. The “x-yplane” refers to the plane congruent with the longitudinal andtransverse directions.

As used herein, the term “impermeable” generally refers to articlesand/or elements that are substantially not penetrated by aqueous fluidthrough the entire Z-directional thickness thereof under a pressure of1.0 kPa or less. Preferably, the impermeable article or element is notpenetrated by aqueous fluid under pressures of 3.4 kPa or less. Morepreferably, the impermeable article or element is not penetrated byfluid under pressures of 6.8 kPa or less. An article or element that isnot impermeable is permeable.

The term “substrate” as used herein refers to any material, including afilm, an apertured film, a nonwoven web, a woven web, a foam or acombination thereof, or a cellulosic material including wood pulp,derivatized or modified cellulosic materials, and the like, having asingle layer or multiple layers. The term “fibrous substrate” as usedherein refers to a material comprised of a multiplicity of fibers thatcould be either a natural or synthetic material or any combinationthereof, including, for example, nonwoven materials, woven materials,knitted materials, and any combinations thereof.

The term “nonwoven” as used herein refers to a fabric made fromcontinuous filaments and/or discontinuous fibers. Nonwoven fabricsinclude those made by carding staple fibers, airlaying or wet layingstaple fibers and via extrusion processes such as spunbonding and meltblowing. The nonwoven fabric can comprise one or more nonwoven layers,wherein each layer can include continuous filaments or discontinuousfibers. Nonwovens can also comprise bi-component fibers, which can haveshell/core, side-by-side, or other known fiber structures.

By “stretch zone”, it is meant a portion of a region of an absorbentarticle having elastic stretch properties. A stretch zone may extendthroughout an entire region or feature of the article, extend acrossmultiple regions or features, or comprise merely a portion of, one ormore regions or features of the article. A region or feature may alsocomprise an array of individual stretch zones.

The term “Line of Force” describes the pathway through a web material orstructure comprising such web material that is substantially parallel toits surface, that connects two points, zones, or features in thematerial, and that carries most of the tension when tension is imposedbetween those two points, zones, or features. The term also applies topluralities of pathways of close enough proximity, properties, anddirection that they effectively behave as a single pathway. The shape,width, and stress/strain behavior of the pathway can be controlled bymodifying the stress/strain properties of the material in the desiredlocation and direction of the pathway to produce a higher effectivemodulus in the pathway compared to areas adjacent to the pathway. Theproportion of the tension carried by the pathway depends on thedifference in effective modulus between the pathway and the adjacentmaterial. It should be understood that a line of force may be defined byany of the stretch element geometries disclosed herein.

Preferred Embodiments

In accordance with one aspect of the invention, an absorbent article isprovided that comprises a liquid permeable topsheet, a liquidimpermeable backsheet, and an absorbent core disposed between thetopsheet and the backsheet. The article may also include one or morefeatures such as, but not limited to, ears or side panels, leg cuffs,fastener components, and/or a belt. The absorbent article according topresent invention is also provided with one or more stretch zones. Inmost cases such stretch zones will comprise at least a portion of theaforementioned features. In other aspects of the invention, the stretchzones comprise a substrate having an elastomeric composition disposedthereon. The elastomeric composition provides an elastic resistance tothe stretch zone upon elongation of at least a portion of the stretchzone. In preferred embodiments of the present invention, the elastomericcomposition is disposed on the substrate in a predetermined geometricpattern (i.e., shape and orientation) so as to provide such elasticresistance in a manner that enhances the performance of the feature. Thepattern preferably allows the stretch zone to more efficiently carryanchoring loads and tensile forces induced by application of the articleto the wearer and/or accommodate movement of the wearer, and/or theweight of the article or waste contents of the article than a typicalnon-patterned design.

Suitably, an absorbent article according to the present invention mustcomprise at least one stretch zone wherein the stretch zone comprises anelastomeric composition that is disposed on a substrate so as to atleast partially penetrate the substrate. The area of a stretch zonecomprises at least the portion of the substrate that is covered by theelastomeric composition. Typically, such stretch zones have thefollowing properties: (1) an elastic resistance (i.e., the load at 25%strain) of at least about 0.05 N/cm, preferably from 0.05 N/cm to about50 N/cm, more preferably from about 0.05 N/cm to about 40 N/cm, and mostpreferably from 0.25 N/cm to about 30 N/cm; (2) a percent set of lessthan about 15%, preferably less than about 12% and more preferably lessthan about 10%; and (3) a stress relaxation value of less than about40%, preferably less than about 30%, and more preferably less than about25%. Methods for measuring these properties are given in the TESTMETHODS section below.

In some embodiments an absorbent article may comprise stretch zones thatare associated so as to provide an array thereof. Such an array may bedisposed on only one region or feature of the absorbent article or mayextend across two or more regions or features. The array can compriseintersecting or non-intersecting stretch zones. Also, the stretch zonesin the array can either be parallel to one another or form a non-zeroangle with respect to each other. When the stretch zones in an array arenon-intersecting, individual stretch zones are cut off and theirproperties may be measured. However, when the stretch zones intersectwithin an array, it is not possible to separate individual stretchzones. In such cases, the array should be sampled and evaluated asdescribed in the TEST METHODS section below.

Suitable elastomeric compositions comprise thermoplastic elastomersselected from the group consisting of styrenic block copolymers,metallocene-catalyzed polyolefins, polyesters, polyurethanes, polyetheramides, and combinations thereof. Suitable styrenic block copolymers maybe diblock, triblock, tetrablock, or other multi-block copolymers havingat least one styrenic block. Exemplary styrenic block copolymers includestyrene-butadiene-styrene, styrene-isoprene-styrene,styrene-ethylene/butylenes-styrene, styrene-ethylene/propylene-styrene,and the like. Commercially available styrenic block copolymers includeKRATON® from the Shell Chemical Company of Houston, Tex.; SEPTON® fromKuraray America, Inc. of New York, N.Y.; and VECTOR® from Dexco ChemicalCompany of Houston, Tex. Commercially available metallocene-catalyzedpolyolefins include EXXPOL® and EXACT® from Exxon Chemical Company ofBaytown, Tex.; AFFINITY® and ENGAGE® from Dow Chemical Company ofMidland, Mich. Commercially available polyurethanes include ESTANE® fromNoveon, Inc., Cleveland, Ohio. Commercial available polyether amidesinclude PEBAX® from Atofina Chemicals of Philadelphia, Pa. Commerciallyavailable polyesters include HYTREL® from E. I. DuPont de Nemours Co.,of Wilmington, Del.

The elastomeric composition may further comprise processing aids and/orprocessing oils to adjust the melt viscosity of the compositions to thedesired range. They include the conventional processing oils, such asmineral oil, as well as other petroleum-derived oils and waxes, such asparaffinic oil, naphthenic oil, petrolatum, microcrystalline wax,paraffin or isoparaffin wax. Synthetic waxes, such as Fischer-Tropschwax; natural waxes, such as spermaceti, camauba, ozokerite, beeswax,candelilla, paraffin, ceresin, esparto, ouricuri, rezowax, and otherknown mined and mineral waxes, are also suitable for use herein.Olefinic or diene oligomers and low molecular weight polymers may alsobe used herein. The oligomers may be polypropylenes, polybutylenes,hydrogenated isoprenes, hydrogenated butadienes, or the like having aweight average molecular weight between about 350 and about 8000.

In an important aspect of the present invention, the elastomericcomposition is substantially tackifier free. Tackifiers are well knownin the adhesive arts as a component that is added to an adhesivecomposition so as to increase the adhesive properties (e.g., peel force)thereof. This provides important benefits because, in addition toincreasing tack of an adhesive material, a tackifier acts as aplasticizer for any polymers in the composition with a resultingreduction in tensile properties due to the presence of the tackifier.Preferred embodiments of the elastomeric composition have a very lowpeel force with a standard substrate (304 stainless steel a #2B finishfrom M^(c) Master Carr of Cleveland, Ohio) using the method described incopending U.S. Pat. Application Ser. No. 60/557,272, entitled“Letterpress Application of Elastomeric Compositions”, filed in thenames of Desai, et al. on Mar. 29, 2004 (P&G Case No. 9592P). Suitableelastomeric compositions have a peel force of less than about 3 N/cm,more preferably, less than about 2 N/cm, even more preferably, less thanabout 1 N/cm, and most preferably, less than about 0.8 N/cm whenevaluated using the method described in the aforementioned application.

In one embodiment, a phase change solvent can be incorporated into theelastomeric composition to lower its melt viscosity, rendering thecomposition processable at a temperature of 175° C. or lower, withoutsubstantially compromising the elastic and mechanical properties of thecomposition. Detailed disclosure of the phase change solvents can befound in U.S. patent application Ser. No. 10/429,432.

Alternatively, the elastomeric composition may also comprise lowmolecular weight elastomers and/or elastomeric precursors of the abovethermoplastic elastomers, and optionally crosslinkers, or combinationsthereof. The weight average molecular weight of the low molecular weightelastomers or elastomeric precursors is between about 45,000 and about150,000.

Suitable elastomeric compositions for use herein are elastic withoutfurther treatment and they do not include any volatile solvents whoseboiling point is below 150° C.

In certain embodiments the elastomeric composition may include precursorcomponents that are activated by a post treatment step after theelastomeric composition has been deposited onto the substrate, so as toimprove or enhance its elasticity and other properties includingstrength, modulus, and the like. For example, the thermoplasticelastomers described in copending U.S. patent application Ser. No.10/610605, filed in the name of Ashraf, et al. on Jul. 1, 2003 thatcomprise an elastomeric block copolymer having least one hard block andat least one soft block, a macro photoinitiator, a processing oil, andoptionally, a thermoplastic polymer and/or a crosslinking agent containsuch precursor components. Typically, post-treatments include drying,crosslinking, curing or polymerizing via chemical, thermal, radiationmeans (e.g., ultraviolet radiation or electron beam radiation), andcombinations thereof.

In certain preferred embodiments, a stretch zone or an array of stretchzones may comprise more than one elastomeric composition. In suchembodiments the first composition will have at least one of: a greaterelastic resistance than any of the other elastomeric compositiondisposed onto the stretch zone or array of stretch zones, a reduced setwhen compared to any of the other of the elastomeric compositionsdisposed onto the stretch zone or array of stretch zones and a reducedstress relaxation. Alternatively, certain portions of an array ofstretch zones may comprise a first elastomeric composition and otherportions may comprise one or more different compositions.

The substrate provides a continuous medium for deposition of theelastomeric composition and contributes at least a portion of theultimate strength of a stretch zone. A continuous medium is important,for example for embodiments where the embodiment comprises an arrayhaving spaced apart stretch zones. In certain embodiments (e.g., asprovided by a fibrous substrate), the substrate can further provide asoft, cloth-like feel to the skin for better wearer comfort. Suitablesubstrate materials include but are not limited to: films, aperturedfilms, foams, knitted fabric, woven fibrous webs or nonwoven fibrouswebs as are known in the art. In some embodiments, the substrates areextensible nonwoven webs made of polyolefin fibers or filaments, such aspolyethylene, or polypropylene. The substrate material may be elastic orinelastic, extensible or inextensible, stretchable or non-stretchable.Preferred substrates have a 3-dimensional morphology (i.e., via spacingbetween fibers, projections, holes, etc.) that facilitates thepenetration of the thermoplastic elastomer into the substrate asdescribed below.

Suitable elastomeric compositions are preferably applied to thesubstrate in a fluid or fluid-like state capable of effecting at leastpartial penetration into the substrate Such partial penetration must besufficient so as to provide attachment between the resulting elastomericcomposition and the substrate such that the composite remains intactthrough subsequent process steps, shipment and the article wear cycle.Preferably, the elastomeric composition penetrates only enough toprovide the desired integrity during subsequent processing and use ofthe article. For example, if the substrate is a fibrous substrate, it isbelieved that elastomeric composition penetration to a depth of aboutone or two fiber diameters is sufficient to provide such integrity.Means to accomplish sufficient penetration of the substrate of thethermoplastic elastomer upon deposition onto the substrate includes,among other mechanisms, absorption of the elastomer into the substratematrix, penetration through all or a portion of the thickness of thesubstrate, engulfing or entrapment of 3-dimensional protrusions from thesubstrate (i.e., entanglement between the substrate and thecomposition), penetration of holes in the substrate, wetting of a3-dimensional surface of the substrate, and the like.

To facilitate such partial penetration, the elastomeric compositionsuitably has a melt viscosity from about 1 to about 1000 Pa·s at 175° C,5% strain and a shear rate of 1 s¹ according to the method disclosed inpublished U.S. Pat. Application No. 2003/0091807A1. Preferably, the meltviscosity is between about 5 and about 500 Pa·s, and more preferablyfrom about 10 to about 400 Pa·s. Such elastomeric compositions aresuitable for use in application processes that operate at a lowerviscosity and/or lower temperature than are typical melt extrusionand/or fiber spinning processes.

The elastomeric composition may be applied to a stretch zone to achievea total add-on level of from about 5 to about 200 g/m², preferably fromabout 20 to about 150 g/m², and more preferably from about 50 to about100 g/m².

An array of stretch zones may have open areas not covered by theelastomeric composition ranging from about 5% to about 90% of the totalsurface area of the region, preferably from about 10% to about 60%, andmore preferably from about 20% to about 40%. As will be recognized, therequired open area depends on the specifics or the region or featurewhere the array is disposed. The selective deposition of elastomericcompositions preferably uses less of the materials than would otherwisebe required by the conventional lamination technology using films orsheets. The fibrous substrate in combination with the selectivedeposition of the elastomeric composition can provide the resultingcomposite with lower basis weight and higher breathability than alaminate containing a fibrous web layer and a film or sheet layer.

As will be recognized, the stretch zones described herein may also beused in combination with stretch features described in the art (Suchstretch features include, but are not limited to an elasticized waist,an elasticized belt, an ear, a side panel, a leg cuff, or a fastenercomponent. See below for a discussion of such features in thesection—Diaper Component Description Applicable to All Embodiments ofPresent Invention). As will be recognized, combining the stretch zonesof the present invention with stretch features from the art may providebenefits that neither approach could provide by itself. For example, anelastomeric film could be used to provide a first level of elasticresistance to a stretch feature formed using an elastomeric, breathablethree dimensional composite material as described in U.S. Pat. No.6,303,208 and portions of the stretch feature could further comprisestretch zones of the present invention to enhance the elastic resistancein predefined positions on the stretch feature. Similar structures canalso be made by replacing the elastomeric film with one or moreelastomeric strands or fibers and providing stretch zones according tothe present invention thereto.

Referring to FIG. 1, an absorbent article in the form of an open-styleor taped diaper 10 is depicted. It should be understood that while FIGS.1-3 depict a diaper, the present invention also contemplates otherwearable absorbent articles, such as catamenial and adult incontinenceproducts, that encircle or enclose at least a portion. of a wearer'sanatomy or which are otherwise secured to a wearer. The diaper 10 has alongitudinal centerline 12 and a lateral centerline 14 as a frame ofreference for this discussion. The diaper 10 may have a pair of opposedend edges 16 and 18, a pair of opposed side edges 20 and 22, a rearwaist region 24, a front waist region 26, a crotch region 28 disposedintermediate the front and rear waist regions 26 and 24, respectively,and a pair of leg regions 30 and 32. The exact size of these variousregions vary according to the size of the diaper 10, but generallyspeaking, the crotch region 28, front waist region 26 and rear waistregion 24 represent equal one-third portions along the longitudinalcenterline 12. The leg regions 30 and 32 generally represent theone-quarter areas across the width of the diaper 10 in the crotch region28, and the crotch region 28 itself, represents the remaining centertwo-quarters or one-half the width of diaper 10.

The diaper 10 also may comprise one or more ears or side panels 34, 36,38 and 40 disposed generally laterally outboard of the side edges 20, 22in the front waist region 26 and/or rear waist region 24. In closablediaper 10 at least one fastener element 42 is disposed on one or more ofside panels 34 and 36 and is adapted to be secured to at least a portionof the longitudinally opposing front side panels 38 and 40, or a portionof the outer surface of the front waist region 26 or a componentthereof. An accompanying fastener element 44 is shown in a folded backconfiguration to expose the mechanical fasteners 46, which shown ashooks for a hook-and-loop fastening systems commercially available from3M or Velcro Industries. The fastener element 44 may be capable ofengaging loop material embodied in a landing zone 27 located on theouter surface of the diaper 10.

Any one or more of regions 24, 26, 28, 30, 32, 34, 36, 38, 40, 42 or 44may comprise a stretch zone or array of stretch zones as may be requiredto provide the desired elasticity in accordance with the presentinvention. In this way, the diaper 10 may preferably be configured toadapt to the specific wearer's anatomy upon application and to maintaincoordination with the wearer's anatomy during wear (i.e., the fit shouldremain the same with minimal sagging, achieving sustained fit.). Anyregion of the diaper 10 may include a stretch zone or array of stretchzones. The front waist region 26 and/or the rear waist region 24 and/orside panel regions 34, 36, 38 and/or 40 preferably include at least onestretch zone of thermoplastic elastomer in order to accommodate a widerrange of wearer waist dimensions (i.e., provide a wider fit range)and/or to provide sufficient tension around the waist circumference ofthe wearer. This provides sufficient normal force to the wearer's skinso as to anchor the diaper 10 with respect to the wearer's anatomy,thereby providing sustained fit.

Each stretch zone may have continuous or discontinuous properties in anydirection wherein the varying properties include chemical composition,elasticity, extensibility, maximum elongation, other stress/strainproperties, vectors or angles, basis weight, geometry, dimensions,3-dimensional morphology, visual distinctiveness, and the like. Astretch zone may have continuous properties (e.g., because theelastomeric composition, substrate material, treatment, etc.) hasrelatively homogeneous properties. Alternatively, stretch zones may havediscontinuous properties due to provision of non-homogeneous propertiesthereto. An array may comprise stretch zones having the same ordifferent properties. Suitable stretch zone arrays include a pluralityof straight or curved lines or bands, rectilinear shapes, curvilinearshapes, other regular or irregular geometric shapes, and combinationsthereof which will be described in more detail hereinafter. Two stretchzones may be longitudinally separated or adjacent, laterally separatedor adjacent, or the stretch zones may be at least partially overlappingin such arrays. Within an array, the individual stretch zones may varyin property, geometry, relative orientation, spacing, or elasticity orextensibility. In certain embodiments, at least a portion of at leastone stretch zone may be visually distinct. Stretch zones may be combinedwith other elastic, extensible, or inextensible materials, such asfilms, webs, strands, and the like to form laminates.

An exemplary diaper chassis comprising arrays of stretch zones is diaperchassis 250 as is shown in FIG. 2. The diaper chassis 250 may include aliquid impermeable backsheet and an outer cover made of a nonwovenmaterial. Other chassis components may be included but are not depictedfor purposes of clearly showing the array of stretch zones of thepresent invention. In one embodiment, a thermoplastic elastomer may bedisposed on a standard liquid impermeable backsheet material in a waywhich creates different arrays of stretch zones in regions 252, 254,256, 258 and 260. By way of example, an array in region 252 may comprisea first thermoplastic elastomer composition, while arrays in regions254, 256, 258 and/or 260 may comprise a different composition orcomprise the first composition disposed in a different configuration(thickness, width, pattern, etc.). In certain cases for purposes ofenhancing fit on a wearer, the various stretch zone properties aresymmetrical in that arrays in regions 252 and 260 have similarproperties, arrays in regions 254 and 258 also have similar propertieswhile an array in region 256 has a third type of elastic property. Itshould be understood, however, that this is not necessary and theindividual arrays in regions 252, 254, 256, 258 and 260 may varyindividually and widely in terms of elastic properties, size, shape, andcomposition without deviating from the scope of the invention.

Reference is now made to FIGS. 3, 4 and 5A-B which show a pant 370. Theterm “pant”, as used herein, refers to disposable garments having awaist opening and leg openings designed for infant or adult wearers. Apant may be preformed by any suitable technique including, but notlimited to, joining together portions of the article using refastenableand/or non-refastenable bonds (e.g., seam, weld, adhesive, cohesivebond, fastener, etc.). A pant may be preformed anywhere along thecircumference of the article (e.g., side fastened, front waistfastened). While the term “pant” is used herein, pants are also commonlyreferred to as “closed diapers”, “prefastened diapers”, “pull-ondiapers”, “training pants” and “diaper-pants”. Suitable pants aredisclosed in U.S. Pat. No. 5,246,433, U.S. Pat. No. 5,569,234, U.S. Pat.No. 6,120,487, U.S. Pat. No. 6,120,489, U.S. Pat. No. 4,940,464, U.S.Pat. No. 5,092,861, U.S. patent application Ser. No. 10/171,249,entitled “Highly Flexible And Low Deformation Fastening Device”, filedon Jun. 13, 2002; U.S. Pat. No. 5,897,545, U.S. Pat. No. 5,957,908.

Pant 370 may include stretch zones to impart the desired elasticproperties so that it can be donned easily and sustain better fit andcomfort. Similar to the diaper 10, stretch zones may be includedanywhere on the pant 370. FIG. 3 is a perspective view of pant 370 andFIG. 4 shows pant 370 in a plan view. As shown therein, pant 370 has alongitudinal centerline 360, lateral centerline 362, a front waistregion 364 (adjacent front waist edge 365), a crotch region 366 and arear waist region 368 (adjacent rear waist edge 369). As can be seenmost clearly in FIGS. 5A-B, pant 370 may include an absorbent assemblyincluding liquid permeable topsheet 372, a liquid impermeable backsheet374, and an absorbent core 376 disposed between the topsheet 372 and thebacksheet 374., An outer cover 378 (typically comprising a nonwoven) isdisposed on the outer surface of the pant 370. Two pair of side panels380, 382 and 384, 386 are attached to the outer cover 378 in the frontwaist region 364 and the rear waist region 368, which in turn, isattached to the backsheet 374 of the absorbent assembly so as to form apair of leg openings and a waist opening for the wearer. Preferably,stretch zones areas are disposed in at least one of the side panels 380,382, 384 and/or 386. The stretch zones of pant 370 may also comprise thewaist regions 364, 366, barrier leg cuffs 388 and 390. For exampleeither or both of the leg elastics 392, 394, and/or the barrier leg cuffelastics 396, 398 could comprise an elastomeric composition where thecomposition is disposed on a substrate so as to form a stretch zone inone of the features shown in FIGS. 5A and 5B.

Belt structures (not shown) may also comprise the stretch zones of thepresent invention. One such alternative structure comprises the earand/or side panel and at least a portion of the waist functionality. Inanother alternative belt structure, a belt completely encircling awearer's waist (i.e., a 360 degree belt) may be formed, for example, bydepositing one or more laterally oriented stretch zones (or an arraythereof) adjacent the front and rear waist edges 365, 369 so as to forma band of tension about the wearer's waist. Such stretch zones couldalso comprise those shown in FIGS. 7A, 7B and 8A-D.

Reference is made to FIGS. 6A-I in which various side panels 604, 606,608, 610 are depicted for a closable open or taped diaper 612. As willbe recognized, the side panels 604, 606, 608, 610 each have an inneredge 634, 636, 638 and 640 disposed at a predefined angle (usuallyparallel) with respect to longitudinal centerline 650. It should beunderstood that the side panels 604, 606, 608 and 610 as describedherein are interchangeable with any of the side panels or ears describedin FIGS. 1-4 of the diapers 10 or 250 or pant 370 and with any of sidepanels 605, 607, 609, 611, 613, 615, 617, and 619 of FIGS. 6B-6I. Thestretch zone arrows 614, 616 are depicted to show exemplary forcevectors desirable of typical side panels in diapers. The size of a givenstretch zone in a region of the diaper 612 is dependent on the functionof the stretch zone and the desired tension/extension vectors 614, 616in that given region of the diaper 612. Each stretch zone may be smalleror larger than the region of the diaper 612 in which it is primarilydisposed. A given stretch zone may also overlap other regions of thediaper 612.

Referring to FIGS. 6B-61, various linear stretch zones 618 of side panel605 may be configured as lines or strands generally having widths lessthan about 2 mm and typically less than about 1 mm. Linear stretch zones618 may also be configured as bands generally having widths betweenabout 2 mm and about 40 mm and aspect ratios ranging from about 2:1 toabout 100:1. Linear stretch zones 618 may also be disposed at an anglewith respect to the lateral centerline 651 (FIGS. 6B and 6F). Preferredangles are in the range 0±70°. Stretch zones having a predominatelylateral orientation are generally wider and have a higher modulus thanthose having a generally longitudinal orientation. Curved stretch zones620 may be either concave or convex with respect to the longitudinal orlateral centerlines 650, 651, or both and may have radii of curvaturegreater than about 1 mm, preferably greater than about 10 mm, morepreferably greater than about 50 mm. The curvature may optionally bevariable over the length or “path” of the stretch zone 620. Typically,the thickness of stretch zones 618 and/or 620 may be in the range ofabout 0.02 mm to about 5 mm and the basis weight is in the range ofabout 20 g/m² to about 300 g/m².

Additional exemplary embodiments of the invention are shown in FIG. 6Cwith side panel 607, FIG. 6D with side panel 609, FIG. 6E with sidepanel 611, FIG. 6F with side panel 613, FIG. 6G with side panel 615,FIG. 6H with side panel 617, and FIG. 6I with side panel 619. All of theside panels 609, 611, 613, 615, 617, 619 may be integral with orseparately attached to the diaper chassis of the diaper 10 or pant 370described previously. Also all of the stretch zones 618 and 620 comprisean elastomeric composition as described herein. FIGS. 6D-6I showadditional stretch zones 622 applied to or formed as part of thefastener element 624 to impart other desired elastic properties of thepresent invention.

Alternatively, one or more, but not all, of stretch zones 618, 620 maycomprise an elastomeric composition that differs from the compositionused to form the remainder of the stretch zones 618, 620. For example,referring to FIGS. 6B and 6C, certain stretch zones 618 that lielongitudinally outboard (i.e., closer to rear waist end 635) of theremainder of stretch zones 618 may comprise an elastomeric compositionwith a higher elastic modulus so as to provide a larger elasticresistance around the circumference of a wearer's waist. Alternatively(FIG. 6B), stretch zones 618 may comprise a first elastomericcomposition and stretch zones 620 may comprise a second elastomericcomposition. Again, stretch zones 618 lie longitudinally outboard ofstretch zones 620.

Alternatively, an array of linear stretch zones 618 or curved stretchzones 620 or both may comprise a spiral or an overlapping or entangledconfiguration, for example a cross hatch array. Suitable stretch zoneshapes (not shown) include rectangles, circles, ellipses, diamonds,triangles, parallelograms, trapezoids, wedges or other sections ofcircles or ellipses, other polygons, or other irregular enclosed shapes.

One particularly preferred embodiment of an array of stretch zones isshown in FIG. 6I where side panel 619 comprises a pair of cross hatcharrays 625, 627. As shown therein, both of arrays 625, 627 comprise aplurality of linear stretch zones 618 in an overlapping, cross hatchpattern where the individual stretch zones 618 have either apredominately lateral orientation or a predominately longitudinalorientation. As will be recognized and described herein, the stretchzones 618 can also be at an angle other than 0° or 90° with respect tothe centerlines.

In one embodiment of side panel 619 shown in FIG. 6I, array 625 hasdifferent mechanical properties than array 627. In particular, firstarray 625 has a lower available strain than second array 625. As usedherein, “available strain” is the strain at which there is an abruptincrease in elastic resistive force in response to an appliedelongation. Such change typically occurs when the applied elongation hasreached the point where a meaningful portion of the resistive force isprovided to a stretch zone by the substrate. At applied elongations lessthan the available strain the elastic resistive force is substantiallyprovided to the stretch zone by the elastomeric composition. Thisdifference in available strain is because array 627 must be able tostretch to a greater extent in order to conform to the full range ofmovement of a wearer's legs. Similarly, first array 625 has differentelastic resistance than second array 627. Suitably, array 625 has anelastic resistance at 25% strain of between about 0.05 N/cm and about 50N/cm, preferably between about 0.1N/cm and about 40 N/cm, morepreferably between about 1 N/cm and about 30 N/cm. The ratio of elasticresistance at 25% elongation of array 625 to the elastic resistance at25% elongation of array 627 is suitably greater than about 1.25:1,preferably greater than about 1.5:1, more preferably between about 2.0:1and about 6.0:1. The difference between available strains of arrays 625and 627 is suitably at least about 25% (i.e., if array 625 has anavailable strain of about 25%, then the available strain of array 627would be at least about 50%), preferably the difference is at leastabout 50%.

Referring to FIGS. 7A and 7B, a diaper 730, similar to diaper 10 andhaving a longitudinal centerline 738, a lateral centerline 739, a rearwaist end 735 and a front waist end 737, is depicted in which the waistand thigh portions of the side panel 732, 733 preferably comprisedifferent stretch zones 734 and 736, varying in tension and/or angle asshown. Preferably, the side panel stretch zone 734 nearer the rear waistend 735 of diaper 730 may be oriented at an angle of about 0 to aboutminus 50 degrees from the lateral centerline 739, more preferablybetween about −5 degrees and about −40 degrees from the lateralcenterline 739. Preferably, the stretch zone 736 may be oriented at anangle of about 0 to about plus 70 degrees from the lateral centerline739, more preferably between about +20 degrees and about +60 degreesfrom the lateral centerline 739. One preferred side panel 732 stretchzone embodiment includes a stretch zone 734 oriented at about −10 to−20° from the lateral centerline 739 and a stretch zone 736 oriented atabout +20° to +50° from the lateral centerline 739.

In certain preferred embodiments, at least one of the side panel stretchzones 736 may be aligned with the end of the outer leg cuff elastics740, 742 in order to provide an effective extension of the leg cuffelastic, thereby encircling a wearer's leg with a combination of stretchzone 736 and 740, 742 shown in FIG. 7B. That is, the outer leg cuffelastics 740, 742 and the side panel stretch zones cooperate to providea substantially continuous line of force to encircle a wearer's legs.

In other preferred embodiments, at least one of the waist regionsadjacent rear waist end 735 or front waist end 737 is also provided withone or more waist stretch zones 744, 745, 746, 747. In such embodimentsthe waist stretch zones 744, 745, 746, 747 may be aligned with the earstretch zones 734 that are disposed adjacent to the rear waist end 735so as to provide a substantially continuous line of force encircling awearer's waist. Depending on the design of diaper 730, such a line offorce may follow the low motion zone of a wearer (see below) or bejuxtaposed with another portion of a wearer's anatomy while encirclingthe waist.

Regardless of the specific construction, composition, or geometry, orstretch properties of the side panel 732, the stretch zones 734 and 736in the waist and thigh portions are preferably capable of substantiallyindependent action with respect to one another. Certain embodiments mayinclude an additional side panel stretch zone (not shown) functioning asa transition between the leg and thigh portions, i.e., a “transitionzone”. The transition zone may have distinctly different stretchproperties (or even not be elastic at all) than either the leg or waistzones and functions to decouple or separate the deformations caused bythe leg and waist panels, allowing them to act independently withoutinteraction with each other. In embodiments comprising a side paneltransition zone, the transition zone may be substantially extensible tofurther promote independent action between the waist and thigh zones ofthe side panel, while still providing sufficient stretch to accommodatethe relative movements of the waist and thigh zones while being worn bya wearer, helping to control buckling and/or folding of the transitionregion.

Referring to FIGS. 8A-D, at least one array 850 of stretch zones 851 maybe included in the waist region of the diaper 830. The array 850 ofstretch zones 851 may have similar or varying degrees of elasticity orextensibility and may assume any geometry or orientation. For example,in FIG. 8A the array 850 of stretch zones 851 is located at the waistend 835 of diaper 830, whereas FIG. 8B shows another embodiment in whichthe array 850 is offset from waist end 835. It may be preferable to havearray 850 located generally in the lower back waist area as shown on apartial side view of wearer 852 in FIG. 8C. In this way, the maximum fitand comfort will be experienced by the wearer 852 as the tension isapplied by the article to the wearer's body at or immediately above theconvexity of the buttocks (i.e., the “buttocks shelf”), contributing tothe overall anchoring capability of the article (i.e., its ability toresist sagging). Said another way, the array 850 and stretch zones 862,864, 866, 868 and 870 (shown in FIG. 8D) co-operate to maintain diaper830 in an optimal fit configuration with respect to the low motion zone853 (i.e., the line or zone connecting the lumbar curve of the back overthe hips to under the abdominal crease of a wearer's body 852) so as tomaximize the performance thereof. For a more detailed discussion of lowmotion zones see U.S. Pat. No. 5,358,500.

In certain preferred embodiments as shown in the partial plan view ofdiaper 830 in FIG. 8D, array 850 comprises one or more stretch zones 854having higher localized elastic resistances (i.e., a “high tension”stretch zone 854) aligned with the waist end 835. The high-tensionstretch zones 854 may be adjacent the waist end 835 or may be disposedinboard thereof. Typically, the high-tension stretch zones 854 aredisposed between about zero and 30 mm from the waist end 835 of thediaper 830. Preferably, the high-tension stretch zones 854 are disposedless than about 20 mm from the waist end 835. Generally, an array 850 ofthe high-tension stretch zones 854 may correspond to an area 856 on thewearer 852 body immediately above or at the upper curvature of thebuttocks 858 where the high-tension stretch zone 854 functions toprovide additional anchoring capability for the diaper 830 by applying anormal force to the geometric “shelf” created by the buttocks 858. Thehigh tension stretch zones 854 additionally hold the waist end 835 ofthe diaper 830 against the wearer's back 860 preventing back waistgapping.

In embodiments comprising an array 850 of stretch zones 854 at or nearthe waist end 835 of diaper 830 and extending through multiple regionsof the back waist and crotch of the article, the remaining area of thewaist end 835 may have either a lower elastic resistance, may beprimarily extensible, or may comprise areas with either property. In anycase, this waist end 835 area (i.e., the area not including the stretchzones 850 or 854) may be a low-tension zone.

Referring again to FIG. 8D, stretch zones 862 may be substantiallyparallel to the proximal edges 864 and 866 of side panels 832 and 833,respectively. Optionally, transition stretch zones 868 and 870 may bedisposed intermediate stretch zones 854 and 868, 870. The stretch zone854 may provide a primary anchoring function and stretch zones 862, 868and 870 may provide a dynamic leg motion accommodation function. Whilestretch zones 854, 868 and 870 all provide an elastic resistance, thepresent invention allows tailoring such forces in both to degree anddirection to meet the different needs of the anchoring and motionaccommodation functions. Referring again to FIG. 8C, preferably, theregion covering a wearer's buttocks 858 comprises at least oneextensible stretch zone so as to provide adequate coverage thereof,conform to the wearer 852 shape, and relieve stress in the transitionregion between the crotch as and the waist end 835 region of the diaper830 (FIGS. 8 A, B and D) as it goes between the wearer 852 legs. Asdescribed previously, side panels 832 and 833 may comprise distinctstretch zones 854, 862, 868 and 870 having different functions and maybe single stretch elements having different properties throughout thestretch zone or have physical delineations between stretch zones 854,862, 868 and 870 such as slits, holes, or other deformation. However,stretch zones 854 and 862 preferably comprise stretch elements, orarrays of stretch elements, having different properties, geometry,and/or dimensions from each other Typically, stretch zones 854 exhibitan elastic resistance of at least about 0.05 N/cm when strained to 25%elongation. Preferably, stretch zone 854 exhibits an elastic resistanceof between about 0.05 N/cm and about 50 N/cm when strained to 25%elongation, more preferably between 0.1 N/cm and about 40 N/cm and mostpreferably between 1 N/cm and about 30 N/cm. Preferably, stretch zones854 experience less than about 40% force relaxation and less than about15% set. Typically, stretch zones 854 will have a maximum elongation ofat least about 25%, preferably between about 50% and about 300%.Typically, stretch zones 862 exhibit an elastic resistance of at leastabout 0.05 N/m when strained to 25% elongation. Preferably, the stretchzones 862 exhibits an elastic resistance of between about 0.1 N/cm andabout 8 N/cm when strained to 25% elongation. Preferably, stretch zones862 experience less than about 40% force relaxation and less than about15% set. Typically, stretch zones 862 may have a maximum elongation ofat least about 25%, preferably between about 50% and about 200%.Additionally, stretch zones 868 and 870 may exhibit a lower resistiveforce upon elongation than either stretch zones 854 and 862 at a givenextension. Typically, the ratio of elastic resistance of stretch zone854 to stretch zone 868 or 870 is at least 1.25:1, preferably at least1.5:1, and most preferably between about 2.0:1 and 6.0:1. Regardless ofthe stretch properties of the individual stretch zones 854, 862, 68 and870, the overall tension of the side panels 832 and 833 region whenextended to 25% is preferably less than 20 N, and the force relaxationis less than 40%.

Referring to FIG. 9, showing diaper 910 is depicted in which the frontwaist region 926 may comprise at least one stretch zone 972 The functionof stretch zone 972 is to dynamically accommodate the contraction andexpansion cycles of the wearer's abdomen as the wearer moves and/orchanges position, preventing front waist sagging. Stretch zone 972 ispreferably substantially aligned with the front waist end 918 of thediaper 910. In closable versions of diaper 910 including a fasteninglanding zone 927 disposed in or near the front waist end 918, thelanding zone 927 may be shaped in a configuration presenting a concavity928 to the front waist end 918 of the diaper 910. In these embodiments,stretch zone 972 may at extend into the landing zone concavity 928, asshown in FIG. 9.

While the buttocks region 974 located in the back waist region inproximity to the crotch region 976 as shown on diaper 910 may compriseeither elastic or extensible portions, or a combination thereof, inpreferred embodiments, the buttocks region 974 may be provided with apattern of thermoplastic elastomer so as to provide a low level ofelastic resistance to a stretch zone therein causing the buttocks region974 to better conform to a wearer's anatomy so as to accommodate thelargest wearer circumference (i.e., the buttocks), including the volumeof the absorbent core 950, allowing the buttocks region 974 to have alower on-wearer tension than the rear waist end 916 region. The buttocksregion 974 may have stretch zones with extensibility that allows for asmoother geometric transition from the constricted crotch region 976between the wearer's legs to the side panels 934 and 936 which may havestretch zones similar to those described in FIGS. 9D for anchoring. Thebuttocks region 974 preferably may elongate further than the waist end916 region to accommodate the wearer's anatomic shape.

Referring to FIG. 10, another embodiment, diaper 1030, is shown in whicha stretch zone 1078 in the waist region may be preferably aligned withthe side panels 1032 and 1033 and/or the fasteners 1080 and 1082disposed on side panels 1032 and 1033 in order to create a substantiallycontinuous line of tension around the waist to promote conformingsustained fit. As shown in FIG. 10, the stretch zone 1078 preferably atleast partially overlaps one of the two imaginary lines 1084 and 1086that connect the longitudinally outboard edges 1092, 1094 of fasteners1082.

Referring to FIG. 11, an array 1104 of stretch zones is shown on diaper1110 in the front crotch region 1128 spanning into the front waistregion 1126. The stretch zones comprising array 1104 may be primarilyparallel to longitudinal centerline 1112 of the diaper 1110 allowingbetter fit in the front crotch region 1128 by providing an elasticresistance along the centerline 1112 as depicted by arrow 1106. Array1104 should only have a low elastic resistance so as not to pull thefront of diaper 1110 down, resulting in sagging. Also, array 1104 shouldhave low available strain so that it hits a force wall after straining asmall amount in the machine direction for improved coverage in the frontwaist area. Typically, array 1104 provides an elastic resistance at 25%strain of between about 0.005 N/cm and about 5 N/cm preferably betweenabout 0.01 N/cm and about 2 N/cm. In certain embodiments the elasticresistance ranges from about 0.1 N to about 1 N/cm.

The available strain of the array 1104 in the machine direction is lessthan about 100%, preferably less than about 50% and more preferably lessthan about 25%. For the whole diaper, the maximum extension in themachine direction at a load of 5 N is less than about 20 cm, preferablyless than about 10 cm, and more preferably less than about 5 cm.Preferably, the area of greatest extensibility is substantially alignedwith and overlapping the longitudinal centerline 1112. In anotherembodiment, array 1104 can be replaced by an individual stretch zone(not shown) providing an equivalent elastic resistance. Preferably, thearea of greatest extensibility is substantially aligned with andoverlapping the longitudinal centerline 1112. In another embodiment,array 1104 can be replaced by an individual stretch zone (not shown)providing an equivalent elastic resistance. Alternatively, array 1104may also comprise stretch zones laterally outboard of and at an angle tothe longitudinal centerline 1112 and diverging toward the front cornersof diaper 1110 as shown by arrows 1108 and 1109 in FIG. 11. These linesor arcs of tension may be primarily elastic so as to provide suitablesuspension for the absorbent core and wearers' waist held therein by“connecting” these loads to the anchoring zones of the article viasuitable lines, or “paths” of tension. Alternatively, these “loaddistribution elements” may comprise lines, arcs, bands, or othergeometric regions of inextensibility in the surrounding areas of crotchregion 1128 and front waist region 1126 and may extend to accommodatethe wearer's rise, while the outboard inextensible load distributionelements provide support for a waste load.

Referring to FIG. 12, another embodiment, diaper 1210 is shown in whichleg regions 1230 may comprise stretch zones 1212 and 1214. Preferably,stretch zones 1212 and 1214 are substantially parallel to longitudinalcenterline 1205 and are highly elastic. Alternatively, stretch zones1212 and 1214 may also be curvilinear or at an angle to the longitudinalcenterline 1205. Portions of the leg regions 1232 may comprise one ormore additional extensible stretch zones 1216 and 1218 that are orientedat an angle to the longitudinal centerline 1205 of diaper 1210.Typically, stretch zones 1216 and 1218 may be at an angle of about 45degrees to about 90 degrees, and preferably at an angle of 45 to 60degrees, from the longitudinal centerline 1205.

In yet another embodiment of the present invention, the stretch zonesdescribed herein can also be provided to a topsheet. For example, diaper1310 is shown in FIG. 13. Diaper 1310 comprises a topsheet 1324, abacksheet 1326 and core 1328 therebetween. Topsheet 1324 has also beenprovided with aperture 1330 which has a periphery 1340. As can be seenin FIG. 13, topsheet 1324 is further provided with a pair of laterallyopposed stretch zones 1343, 1344 which also comprise a portion ofperiphery 1340. Stretch zones 1343, 1344 extend from front waist region1336 through crotch region 1337 to rear waist region 1338. Stretch zones1343, 1344 provide an elastic resistance causing diaper 1310 to assume acup-like configuration in the relaxed state shown in FIG. 13. Thiselastic resistance helps insure desirable bodily contact betweentopsheet 1324 and a wearer's body. In the preferred embodiment shown inFIG. 13, this bodily contact helps insure that aperture 1330 andtopsheet 1326 combine to create a sag tolerable anal cuff to helpisolate bodily waste from contact with the wearer's body. Such cuffs aredescribed in greater detail in copending U.S. Patent ApplicationPublication No. 2004/0193134 A1 entitled “Articles with Cuffs”, filed inthe name of Mueller, et al., published on Sep. 30, 2004.

Diaper Component Description Applicable to all Embodiments of PresentInvention

All of the embodiments in FIGS. 1-13 have diaper components which maytake any one or more of the materials, designs, and methods of assemblydescribed hereinafter without departing from the scope of the presentinvention. While any of the article components may be assembled in avariety of well known configurations, exemplary diaper configurationsare described generally in U.S. Pat. No. 3,860,003; U.S. Pat. No.5,151,092; and U.S. Pat. No. 5,221,274; and U.S. Pat. No. 5,554,145;U.S. Pat. No. 5,569,234; U.S. Pat. No. 5,580,411; and U.S. Pat. No.6,004,306.

Exemplary breathable materials may include materials such as woven webs,nonwoven webs, composite materials such as film-coated nonwoven webs,microporous films such as manufactured by Mitsui Toatsu Co., of Japanunder the designation ESPOIR NO and by Exxon Chemical Co., of Bay City,Tex., under the designation EXXAIRE, and monolithic films such asmanufactured by Clopay Corporation, Cincinnati, Ohio under the nameHYTREL blend P18-3097 Some breathable composite materials are describedin greater detail in U.S. Pat. No. 6,187,696; U.S. Pat. No. 5,938,648;U.S. Pat. No. 5,865,823; and U.S. Pat. No. 5,571,096.

The article may include a structural elastic-like film web is anextensible material that exhibits an elastic-like behavior in thedirection of elongation without the use of added elastic materials andis described in more detail in U.S. Pat. No. 5,518,801. In alternateembodiments, the backsheets may comprise elastomeric films, foams,strands, or combinations of these or other suitable materials withnonwovens or synthetic films.

Exemplary absorbent structures for use as the absorbent core aredescribed in U.S. Pat. No. 4,610,678; U.S. Pat. No. 4,673,402; U.S. Pat.No. 4,834,735; U.S. Pat. No. 4,888,231; U.S. Pat. No. 5,137,537; U.S.Pat. No. 5,147,345; U.S. Pat. No. 5,342,338; U.S. Pat. No. 5,260,345;U.S. Pat. No. 5,387,207; and U.S. Pat. No. 5,625,222.

Suitable absorbent and nonabsorbent sublayers are described in EuropeanPatent Application No. EP 0 847 738 A1 and U.S. Pat. No. 5,941,864.Further, the sublayer, or any portion thereof, may include or be coatedwith a lotion or other known substances to add, enhance or change theperformance or other characteristics of the element.

Some exemplary surface fastening systems are disclosed in U.S. Pat. No.3,848,594; U.S. Pat. No. B1 4,662,875; U.S. Pat. No. 4,846,815; U.S.Pat. No. 4,894,060; U.S. Pat. No. 4,946,527; the herein beforereferenced U.S. Pat. No. 5,151,092; and U.S. Pat. No. 5,221,274. Anexemplary interlocking fastening system is disclosed in U.S. Pat. No.6,432,098. The fastening system may also: provide a means for holdingthe article in a disposal configuration as disclosed in U.S. Pat. No.4,963,140; include primary and secondary fastening systems, as disclosedin U.S. Pat. No. 4,699,622; means to reduce shifting of overlappedportions or to improve fit as disclosed in U.S. Pat. No. 5,242,436;means to resist gapping at a wearer's belly as disclosed in U.S. Pat.No. 5,499,978 in U.S. Pat. No. 5,507,736 and in U.S. Pat. No. 5,591,152.

Suitable training pants and pull-on diapers are disclosed in U.S. Pat.No. 5,246,433; U.S. Pat. No. 5,569,234; U.S. Pat. No. 6,120,487; U.S.Pat. No. 6,120,489; U.S. Pat. No. 4,940,464; and U.S. Pat. No.5,092,861.

Examples of diapers with elasticized side panels are disclosed in U.S.Pat. No. 4,857,067; U.S. Pat. No. 4,381,781; U.S. Pat. No. 4,938,753;the herein before referenced U.S. Pat. No. 5,151,092; U.S. Pat. No.5,221,274; U.S. Pat. No. 5,669,897; U.S. Pat. No. 6,004,306, and theaforementioned U.S. Pat. No. 6,300,208.

U.S. Pat. No. 3,860,003 describes a disposable diaper which provides acontractible leg opening having a side flap and one or more elasticmembers to provide an elasticized leg cuff (a gasketting cuff). U.S.Pat. Nos. 4,808,178 and 4,909,803 describe disposable diapers having“stand-up” elasticized flaps (barrier cuffs) which improve thecontainment of the leg regions. U.S. Pat. Nos. 4,695,278 and 4,795,454describe disposable diapers having dual cuffs, including gaskettingcuffs and barrier cuffs.

Embodiments of the present invention may also include pockets forreceiving and containing waste, spacers which provide voids for waste,barriers for limiting the movement of waste in the article, compartmentsor voids which accept and contain waste materials or any combinationsthereof. Examples of pockets and spacers for use in absorbent productsare described in U.S. Pat. No. 5,514,121; U.S. Pat. No. 5,171,236; U.S.Pat. No. 5,397,318; U.S. Pat. No. 5,540,671; U.S. Pat. No. 6,168,584;U.S. Pat. No. 5,306,266; and U.S. Pat. No. 5,997,520. Examples ofcompartments or voids are disclosed in U.S. Pat. No. 4,968,312; U.S.Pat. No. 4,990,147; U.S. Pat. No. 5,062,840; and U.S. Pat. No.5,269,755. Examples of suitable transverse barriers are described inU.S. Pat. No. 5,554,142; U.S. Pat. No. 6,010,490; and U.S. Pat. No.5,653,703. Examples of other structures especially suitable formanagement of low viscosity feces are disclosed in U.S. Pat. Nos.5,941,864; 5,977,430 and 6,013,063.

The diaper 10 of FIG. 1 is preferably applied to a wearer by positioningone of the waist regions under the wearer's back and drawing theremainder of the diaper between the wearer's legs so that the otherwaist region is positioned across the front of the wearer. The fastenerelements are then used by the caregiver to join the front and rear waistregions so as to encircle the wearer's waist. The elasticized sidepanels will typically be extended and tensioned during this operation soas to conform to the size and shape of the wearer. A pant, such as thatshown in FIG. 3, may be placed in position on the wearer by insertingthe wearer's legs into the leg openings and sliding the pant intoposition about the wearer's lower torso.

Test Methods

Hysteresis Test for Elastic Properties

Overview

This test measures: a) elastic resistance (load at 25% elongation), b)force relaxation, and c) percent set of an individual stretch zone or anarray of stretch zones. The stretch zones can either be intersecting ornon-intersecting. Non-intersecting stretch zones can be either parallelor non-parallel. Ideally, the sample dimension should be 2.54 cmwide×5.08 cm long, with the direction of stretch being the longdimension. Furthermore, ideally, the gage length should be 2.54 cm.Because of the variety of patterns that the stretch can be in, it isnecessary to define different sample preparation procedures fordifferent classes of stretch zones. Once a sample has been prepared, itis stretched according to a predefined regimen to provide data forproperty determination.

Apparatus

-   Tensile Tester:A commercial constant rate of extension tensile    tester from Instron Engineering Corp., Canton, Mass. or SINTECH-MTS    Systems Corporation, Eden Prairie, Minn. (or a comparable tensile    tester) may is suitable. The instrument is interfaced with a    computer for controlling the test speed and other test parameters,    and for collecting, calculating and reporting the data.-   Load Cell Choose the jaws and load cell suitable for the test; the    jaws should be wide enough to fit the sample, typically 2.54 cm jaws    are used; the load cell is chosen so that the expected tensile    response from the sample tested will be between 25% and 75% of the    capacity of the load cells or the load range used, typically a 1 kN    load cell is used;-   Sample Cutter The specific sample cutter is defined by the desired    sample width. Suitable cutters are available from Thwing-Albert    Instrument Co. of Philadelphia, Pa. For a 2.54 cm wide sample a    Model JDC 1-10 is suitable.    Sample Preparation    (i) Sample Preparation for Linear, Non-intersecting Stretch Zones

Cut a sample that is 2.54 cm wide by 5.08 cm long from within anindividual stretch zone. If an individual stretch zone is smaller thanthese dimensions, the sample should comprise the entire stretch zone.Orient the sample in the jaws to ensure that the sample is stretched inthe longitudinal direction of the stretch zone. If the force from anindividual stretch zone is too small to measure on the tensile tester,several samples from identical stretch zones taken from multipleproducts can be pulled collectively in between the grips of the tensiletester, and the data normalized to an individual stretch zone. In thespecial case when all the stretch zones are uniformly spaced apart andparallel to one another, and also have the same dimensions and basisweight of elastomer, a 2.54 cm sample spanning multiple stretch zonescan be tested. The load can then be normalized to an individual stretchzone by dividing the total force by the number of stretch zones.

(ii) Sample Preparation for Non-Linear, Non-intersecting Stretch Zones

The sample dimensions are 6.3 mm width×5.08 cm length. The length ismeasured along the curved path. The width of the sample is small so thatthe curved stretch zone can be approximated as a linear stretch zone.The gage length in the tensile tester is set at 2.54 cm. As mentionedearlier, if it is not possible to obtain a sample of the abovedimensions, then the sample dimensions can be decreased to the largestpossible and the gage length adjusted according.

(iii) Sample Preparation for an Array of Intersecting Stretch Zones

The test sample is 2.54 cm wide×5.08 cm long. If the array is smallerthan these dimensions, the sample should comprise the entire array. Thearray needs to be pulled in the direction close to the direction ofmaximum stretch. This can generally be determined by pulling the samplein several directions (e.g., CD, MD and 45 degrees to CD). If such adirection is not easily discernible, the default direction of pull isthe cross machine direction.

Method

The hysteresis is measured under standard laboratory conditions (25°C.±2° C. and relative humidity of about 50%±2.0%).

The procedure for determining hysteresis of an elastomeric memberinvolves the following steps:

-   1. Calibrate the tester according to the manufacturer's    instructions;.-   2. Set the gauge length at 2.54 cm or as appropriate for the sample    being tested; set the slack preload at 0.05 N.-   3. Place the sample in the flat surface of the jaws such that the    longitudinal centerline of the sample is substantially parallel to    the gauge length direction.-   4. Set the crosshead speed at a constant speed of 25.4 cm/min.-   5. Initiate crosshead motion, the tester begins to record load and    strain data simultaneously. The hysteresis test specifically    involves the following steps:    -   a) elongate the sample to 25% strain at a constant rate of 25.4        cm/min-record the force at 25% elongation;    -   b) allow the sample to remain at this strain for 2        minutes-record the force at the start and end of the 2 minute        period;    -   c) return the sample to 0% strain at a constant rate of 25.4        cm/min;    -   d) allow sample to remain at this strain for 1 minute; and    -   e) elongate the sample to 0.1 N load at a constant rate of 5.08        cm/min-record the strain at 0.1 N (i.e., a force sufficient to        remove slack but low enough to impart, at most, insubstantial        stretch to the sample).        Calculations and Reported Results-   1. From the data collected in step 5(a), the load at 25% strain is    reported as the elastic resistance of the material.-   2. From the data collected in step 5(b), the force relaxation is    determined by the load at the beginning and at the end of the 2    minutes hold time using the following formula:    ${\%\quad{Stress}\quad{Relaxation}\quad{at}\quad{time}},{t = {\frac{\lbrack {( {{initial}\quad{load}} ) - ( {{{load}\quad{at}\quad{time}},t} )} \rbrack}{{initial}\quad{load}} \times 100}}$-   3. From the data collected in step 5(e), the % set is calculated    using the following formula:    ${Percent}\quad{{Set}\lbrack {( \frac{{Strain}\quad{Recorded}\quad{at}\quad 5(e)}{{Gas}\quad{Length}} ) - 1} \rbrack} \times 100$-   4. Report the average results from three replicate samples for each    material tested.    Available Strain

This is intended to determine the Available Strain of a sample. TheAvailable Strain is the point at which there is an inflection in theforce—elongation curve, beyond which point there is a rapid increase inthe amount of force required to elongate the sample further. Anexemplary force (F (N/cm))-elongation (E (%)) curve is shown as FIG. 14.As shown therein, available strain is determined from force elongationcurve 720 as the intersection point 720 b of linear extrapolations ofthe stage 1 portion of the curve 720 a and the stage 2 portion of thecurve 720 c.

Method

-   1. Samples are prepared according to the Hysteresis Test described    above.-   2. Repeat steps 1-4 of the Hysteresis Test.-   3. Initiate crosshead motion. The tester begins to record load    versus strain (percent elongation) data simultaneously;-   4. Continue elongating the sample until either:    -   a) the sample breaks; or    -   b) the force limit of the load cell is reached.-   5. Plot the force/elongation data to create a curve similar to that    shown in FIG. 14.-   6. Extrapolate the stage 1 and stage 2 portions as shown to    determine the available strain.-   7. Report the average results from three replicate samples for each    material tested.

All documents cited in the Detailed Description of the Invention are, inrelevant part, incorporated herein by reference; the citation of anydocument is not to be construed as an admission that it is prior artwith respect to the present invention.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

1. An absorbent article, said absorbent article having a waist region, acrotch region, a longitudinal centerline and a lateral centerline, saidabsorbent article comprising at least one stretch zone, said stretchzone comprising a first substrate having a first thermoplasticelastomeric composition disposed thereon in a predetermined geometricpattern defining said stretch zone.
 2. An absorbent article according toclaim 1 wherein said stretch zone comprises at least a portion of afeature selected from the group consisting of a waist feature, an ear, aside panel, a leg cuff, a fastener component and combinations thereof.3. An absorbent article according to claim 2 wherein two of saidfeatures are in an abutting relationship and said stretch zone comprisesat least a portion of each of said abutting features.
 4. An absorbentarticle according to claim 2 wherein said two of said features are saidwaist feature and said ear.
 5. An absorbent article according to claim 2wherein said two of said features are said leg cuff and said ear.
 6. Anabsorbent article according to claim 1, said stretch zone having aproperty selected from the group consisting of differing widthdimensions between said individual stretch zones, differing thicknessdimensions between said individual stretch zones, differing spacingbetween said individual stretch zones, differing mechanical propertiesbetween said individual stretch zones, differing visual appearance anddiffering permeability between said individual stretch zones wherein,when at least one of said properties is measured at each of two pointsalong a line in a direction parallel to said longitudinal centerline,there is a variation between the value of said property.
 7. An absorbentarticle according to claim 6 wherein said variation is defined as theabsolute value of the measurement of the property at said first pointminus the value of said property at said second point divided by thevalue of said property at said first point and said variation is greaterthan about 0.1
 8. An absorbent article according to claim 1, saidstretch zone having a property selected from the group consisting ofdiffering width dimensions between said individual stretch zones,differing thickness dimensions between said individual stretch zones,differing spacing between said individual stretch zones, differingmechanical properties between said individual stretch zones, differingvisual appearance and differing permeability between said individualstretch zones wherein when at least one of said properties is measuredat each of two points along a line in a direction parallel to saidlateral centerline there is a variation between the value of saidproperty.
 9. An absorbent article according to claim 8 wherein therealso is a variation in at least one of said properties in a directionparallel to said longitudinal centerline, said variation being definedas the absolute value of the measurement of the property at a firstpoint minus the value of said property at a second point along a lineparallel to said longitudinal centerline divided by the value of saidproperty at said first point.
 10. An absorbent article according toclaim 8 wherein said variation is defined as the absolute value of themeasurement of the property at said first point minus the value of saidproperty at said second point divided by the value of said property atsaid first point and said variation is greater than about 0.1.
 11. Anabsorbent article according to claim 1 wherein said stretch zone is usedin combination with an elastic element, said elastic element beingselected from the group consisting of an elastomeric film an elastomericstrand and an elastomeric fiber.
 12. An absorbent article, saidabsorbent article having a waist region, a crotch region, a longitudinalcenterline and a lateral centerline, said absorbent article comprisingat least a first stretch zone and a second stretch zone, at least one ofsaid stretch zones comprising a first substrate having a firstelastomeric composition disposed thereon defining said stretch zone suchthat said elastomeric composition at least partially penetrates saidfirst substrate wherein said first stretch zone differs from said secondstretch zone in a property selected from the group consisting ofdiffering width dimensions between said individual stretch zones,differing thickness dimensions between said individual stretch zones,differing spacing between said individual stretch zones, differingmechanical properties between said individual stretch zones, differingvisual appearance and differing permeability between said individualstretch zones.
 13. A absorbent article according to claim 12 whereinsaid differing stretch zones at least partially overlap.
 14. Anabsorbent article according to claim 12 wherein said stretch zonesdiffer in at least one mechanical property, said mechanical propertybeing selected from the list consisting of elastic resistance, percentstress relaxation at 2 minutes, percent set, and available strain. 15.An absorbent article according to claim 12 wherein said absorbentarticle comprises a first array having a first elastic resistance and asecond array having a second elastic resistance wherein a ratio of saidfirst elastic resistance to said second elastic resistance is greaterthan about 1.25:1.
 16. An absorbent article according to claim 12wherein said first stretch zone comprises at least a portion of afeature selected from the group consisting of a waist feature, an ear, aside panel, a leg cuff, a fastener component and combinations thereof.17. An absorbent article according to claim 16 wherein two of saidfeatures are in an abutting relationship and said stretch zone comprisesat least a portion of each of said abutting features.
 18. An absorbentarticle according to claim 17 wherein said two of said features are saidwaist feature and said ear.
 19. An absorbent article according to claim17 wherein said two of said features are said leg cuff and said ear. 20.An absorbent article according to claim 12 wherein said stretch zone isused in combination with an elastic element, said elastic element beingselected from the group consisting of an elastomeric film an elastomericstrand and an elastomeric fiber.